The present invention relates to an antenna system, in particular, relates to a whip antenna which is used in a portable transceiver or a portable telephone set, which high gain of an antenna is obtained even when an antenna is retracted.
In a portable transceiver and/or a portable telephone set, it must operate even in a waiting state in order to receive a call, and therefore, an antenna must have high gain to receive a call. However, an antenna is usually retracted in a housing of a telephone set when a telephone set is in a waiting state. Therefore, it is desirable that an antenna has high gain not only when an antenna is extended, but also when an antenna is retracted.
In order to solve the above problem and have high gain in the antenna in retracted state, the U.S. Pat. No. 4,865,576 has been proposed. That antenna has an outside antenna rod which has a coil element at the bottom of the rod, a meander line type ground radiator, and a meander line antenna installed in a housing.
However, it has the disadvantages that the structure of the antenna is complicated, and the gain of an antenna when it is extracted is rather low, because of the relation from the coil and the meander line interfering with the radiation from the extended antenna rod, although the gain at retracted state is high by reason of those radiations.